Soap and lubricant containing the same



Patented Sept. 8, 1942 soar AND wnmcm con-rename rm: SAME Reuben A.Swenson, Hammond, Ind., assignor to Standard Oil Company, Chicago, 111.,a corporation of Indiana No Drawing. Application March 29, 1940, SerialNo. 326,785

21 Claims.

This invention relates to a new soap, particularly adapted for use inlubricants, such as greases. More particularly it relates to, greasescontaining this new composition of matter. Still more particularly itrelates to the making of the new soap and to itsuse in making greases.

Soda soaps and lead-fish oil soaps and mixtures of the two are wellknown as bases for the manufacture of lubricants. For many purposes suchlubricants have been found to be entirely satisfactory. However, underconditions of extreme pressure, particularly where high temperature isalso encountered neither .these lubricants nor those containing otherbases have been found to be entirely satisfactory in use either from thepoint of view of lubrication or consumption. Moreover, lubricants whichhave otherwise satisfactory properties frequently do not have sufficientresistance to water or cannot be readily applied at normal temperatures.

It is an object of this invention to provide a new soap. Another objectis to provide a method for making the new soap. A further object is toprovide a new soap particularly adapted for use in lubricants. A stillfurther object is to provide lubricants containing a new soap. A stillfurther object is to provide lubricants having increased resistance toheat and water and increased adhesion adapting them for use under severeconditions of pressure and which may be readily applied at moderatetemperatures. Other objects will appear hereinafter.

It has now been found that these objects may -be accomplished byreacting sodium hydroxide In the preparation of my complex soap I preferto first make a heavy metal soap by reacting a heavy metal-oxide such aslead oxide (litharge) with a fatty oil. This soap is made by reacting 3moles of lead oxide or litharge with 1 mole of a fatty oil such as afish oil. In order to prepare my complex soap hereinafter described itis desirable to have an excesssof fatty oil present over that requiredto react 3 moles of litharge with 1 mole of the-fatty oil. Since thesoap becomes too stiff to permit effective agitation during the re-'acting period it is desirable to add a diluent to the mixture in orderto make the product more fluid. Where the product is to be compounded tomake a lubricant a mineral oil of the desired viscosity may be used asthe diluent. The viscosity of the mineral oil and the quantity used maybe varied considerably depending upon the type of lubricant to beprepared. Preferably about by weight of oil may be used but higherproportions as well as lower proportions ranging down to about 10% andlower may be used if desired.

A mixture of the fatty oil and the desired quantity of mineral oil isheated to about 300 F. and a smallpart of the required litharge is addedwith efficient stirring. As the reaction proceeds the litharge is addedmore rapidly while maintaining the reaction temperature at about 300 F.The mixture is agitated and maintained at this temperature until thereaction is completed. Lower temperatures may be employed but the timefor completing the reaction will be materially increased. For the bestresults the temperature should not be permitted to exceed about 325 F.

The appropriate amount of lead oxide which should be employed with anysuitable fatty oil can readily be'calculated from the saponiflcationnumber of the oil. l he method of preparing the heavy metal component ofmy complex soap is described in detail in U. S. Patent No. 1,830,984.

Lead soap prepared in the manner just described is then converted intothe new complex sodium-lead soap by reacting sodium hydroxide with thelead soap just described. This is accomplished by adding an excessiveamount of sodium hydroxide over that required to saponify the additionalfatty oil that is added in the preparation of the complex soap.Preferably the amount of caustic employed should equal about 1 mole ofcaustic per mole of heavy metal. The reaction between the sodiumhydroxide and the lead soap takes place at an elevated temperature.

The reaction may be initiated at temperatures of the order of about F.to about 200 F. and thereafter the reaction is carried to completion ata temperature of about 400 F. By completing the reaction at the hightemperature the reaction time is considerably reduced and any waterpresent in the final product is substantially eliminated. In carryingout this reaction it is preferable to have a diluent present in order tofacilitate eflicient agitation of the reaction mixture. Such a diluentmay be, for example, the petroleum oil called for by the lubricantformula where the sodium-lead soap is being made for use in a particularlubricant.

While I have described the preparation of the complex sodium-lead soapthe same has been used only by way of example, it being understood, ofcourse, that in place of sodium hydroxide any one or more of the alkalior alkaline earth metal bases of groups I and II of the periodic table,such as calcium hydroxide, barium hydroxide or potassium hydroxide maybe so employed.

Although the formation of the new complex sodium heavy-metal soap hasbeen described above without regard to the preparation of any particularlubricant, in actual practice, as has been indicated, the new soap isusually formed in the course of the preparation of the lubricant inwhich it is intended to be used. The heavy metal oxide-fatty oilreaction product is, however, in the usual procedure made up in advance.It is desirable that the concentration of the heavy metal soap in thebase oil be substantially at its maximum as it is easier to decreasethis concentration in making up lubricants than it is to increase it.The lead fish oil soap, when so made up is very stiff and difficult tohandle, and, as explained above, for uniform reaction and ease inhandling, a diluent is desirable. Since petroleum oils having SayboltUniversal viscosities at 100 F. ranging from about 80 to about 2500seconds are constituents of a large number of lubricants containing mycomplex alkali-lead oxide soap and also are well adapted for use as adiluent, the reaction between lead oxide and the fatty oil is usuallycarried out in the presence of an oil within this viscosity range. Thequantity of such petroleum oil which should be used will depend upon anumber of factors such as the viscosity of the oil, the formula of thedesired lubricant, etc. A particularly convenient procedure where thesoap is formed from litharge and menhaden oil using the maximum quantityof litharge, (i. e. about 80% by weight, based on the menhaden oil) isto have present as a diluent an amount of the desired petroleum oilequal in weight to the combined weight of the litharge and menhaden oil.

This base, identified as the lead-fish oil soap base, is then added to asubstantial portion of the additional petroleum oil called for by theformula of the lubricant, preferably about an equal weight, in a vesseladapted to be heated, for example, a fire kettle, and heated preferablyto about 400 F. or somewhat higher. The petroleum oil to which the baseis added, may be, for example, a blend of about 50% to about 70%residuum (furol viscosity at 210 F. of about 800-900 seconds), and about50% to about 30% low viscosity petroleum oil having a Saybolt viscosityat 100 F. of about 80-300 seconds. If additional fish oil or other fattyoil is to be used it is also added at this point.

The mixture is then heated, for example, to a temperature of about 160to about 200 F. and sodium hydroxide is added. The quantity of sodiumhydroxide should be substantially in excess of that required to saponifythe excess fatty acid present in the 50% base. Preferably, as pointedout above, the excess of sodium hydroxide should be equal to 1 mole ofsodium hydroxide for each mole of lead oxide present in the base. Theexcess sodium hydroxide may, however, if desired exceed even this amountto some extent.

Reaction takes place at the elevated temperature and is preferablyaccelerated by raising the temperature to about 200 to 220 F. after theaddition of sodium hydroxide. Still further elevation of thetemperature, particularly after a heavy base is formed is alsodesirable. Thus, for example, after the heavy base is formed it ispreferred that the temperature be raised gradually to about 400 F. orsomewhat higher.

If the formula of the lubricant calls for ingredients not yet includedthey may be added by grading them in at this point. For example, theformula may call for additional petroleum oil over that alreadyincorporated. During such additions the temperature is preferably kepthigh, for example, at about 400 F. In order that the mixing of the addedmaterials may be completed it is desirable to maintain the elevatedtemperature and stir for about hour or longer after the addition iscomplete.

The lubricant may now be filled at the high temperature to which it hasbeen heated, for example, about 400 F. or at a lower temperature. Asmoother product is usually obtained if the mass isstirred to about 300F. to 250 F. before filling. Additional desirable characteristics suchas stringiness may be obtained by adding high molecular weight syntheticpolymers such as high molecular weight iso-olefin or mono-olefinpolymers before filling. Fillers, such as asbestos, talc or graphite,may also be added before filling.

In order to illustrate exact methods for carrying but the invention thefollowing examples are included. It will be understood that theseexamples are intended to be construed as illustrative only and not aslimiting the scope of the invention.

EXAMPLE I A lead-fish oil soap base is first prepared parts of the lightpetroleum oil and 15 parts of menhaden oil are then added rapidly, thesteam is turned on and the contents of the mixer are heated at 300-325F. for 4 hours, when the reaction is complete. The product is thenfilled into barrels for storage or it can be treated furtherimmediately.

To make the complex sodium-lead-fish oil soap 31.8 parts of the 50%lead-fish oil soap, prepared as above, is added to approximately anequal weight of a suitable blending oil in a fire kettle. The contentsof the kettle are heated to l-200 F. and 3 parts (dry weight) of sodiumhydroxide solution of about 48 B. gravity are added. Reaction iscontinued at 200-220 F. until a heavy base is formed and then thetemperature is gradually raised to 400 F. The resultant product is ahighly heat resistant material which may be blended with otheringredients to produce lubricants suited for a wide variety of uses.

EXAMPLE II A lubricant may be prepared by mixing in a fire kettle 31.8parts of a 50% lead-fish oil soap base (prepared as described in ExampleI in a diluent comprising a low cold test stock having a flash of about300 F. and a Saybolt viscosity at 100 F. of about 80-85 seconds) withapproximately an equal amount of a mixture of parts of a residuum stockhaving a Furol viscosity at 210 F. of about 850 seconds and 35 parts ofa low cold test oil having a flash of about 300- 315 F. and a Sayboltviscosity at 100 F. of about 80-85 seconds. Five parts of menhaden oilare then added and the contents of the kettle are heated to 150-200 F.Three parts (dry weight) of sodium hydroxide solution of about 48 B.gravity are then added and the temperature maintained at 200-220 F.until a heavy base is formed. Thereafter the temperature is raisedgradually to approximately 400 F. to complete the reaction. The balanceof the oil called for by the following formula is then graded in atabout 400 F.

Formula Parts Lead-fish oil soap (50%) 31.8 Menhaden oil 5.0 Sodiumhydroxide 3.0

. Winkler C. C. stock (residuum stock having a 'Furol viscosity at 210F. of about 850 seconds) 49.5 300 flash L. C. T. stock (low cold testoil having a flash of about 300-315" F. and

a Saybolt viscosity at 100 F. of 8085 seconds) 10.7

After all the oil has been added the batch is stirred as it cools to 300F., at which temperature it is filled. The product is an excellentlubricant for heavy, loose running machinery, particularly gears exposedto high temperatures, such as the table roll gears, side roll gears,driving pinion gears and bevel gears, etc. found on steel millmachinery. Lubricants of this type are known in the art as gear shieldlubricants. When heated to 500600 F. on a hot plate it maintains itsgrease structure without flowing appreciably over an extended heatingperiod almost to the point of carbonization. No similar type oflubricant is known which will maintain its structure at such a hightemperature for even half the time that the product of this examplewill. Substantial neutrality and freedom from water also characterizethe material. It is also non-fibrous, smooth and unctuous and adherestenaciously to metal surfaces.

EXAMPLE III The lubricant of Example II is quite satisfactory for use inmoderate or warm weather but because of its high oil viscosity it isdiflicult to apply in cold weather. A better lubricant from thestandpoint of cold weather application has The lubricant is formed inthe same manner as that described in Example II by first making a 50%lead-fish oil soap with 5.95 parts litharge, 7.55 parts menhaden oil and13.5 parts 300' flash Ii. 0. T. stock. The 27 parts of lead-fish oilsoap base are then combined with the other ingredients as in Example II.

- those equipped with pressure gun fittings.

cellent lubricant for leaf springs, particularly This was established ina test very closely simulating The resulting product is of the samegeneral nature as that produced-in Example II except that it is softerand more free flowing at low temperatures. It has been found to be anex- 7 actual service conditions.

In conducting this test a spring is dismantled. cleaned with a petroleumsolvent, dried and reassembled. It is then placed in the testing ma-.chine which flexes the spring repeatedly. The spring is then lubricatedwith the grease under test and the machine is then started and runcontinuously until squeaking occurs. The results of the test were asfollows:

Lubricant No. of hours before squeaking C Product of Example III 72.More than 214 (test discontinued).

Lubricant .8 is made according to the formula of a large automobilemanufacturer.

Lubricant 0" is a special lubricant made up for test purposes.

At the start of each test there is an initial period of squeaking thatlasts until the lubricant spreads throughout the leaves. In the abovetest, this initial squeaking period was very short .where the lubricantof Example III was used, indicating that it spreads rapidly between theleaves. The test on this product was discontinued after 214 hours sincethere was no practical value in running it any longer but'examination ofthe springs leaves after the test disclosed an ample coverage 'oflubricant so that undoubtedly the test would have continued for a muchlonger period before squeaking would have occurred. Thus the testindicates that the new grease'is superior both in its ability to spreadrapidlybetween the leaves and in its ability to adhere tenaciously tothe leaves during service.

The product of Example III is not only a good spring lubricant, but isalso a very good heavy gear shield lubricant for use during coldweather. The product of Example II is quite satisfactory at moderate orelevated temperature but at low temperatures is somewhat diflicult toapply due to its high oil viscosity. Under these conditions the productof Example III has been shown to be quite satisfactory both as alubricant under severe conditions of pressure and temperature as well asin case of application at low temperatures. The products of bothExamples II and III have been tested as heavy gear shield lubricants inactual service conditions in a steel mill and have both been found to beentirely satisfactory from both effectiveness in lubrication and inconsumption. I

The temperatures and times of reaction indi cated above have been foundto give satisfactory products, but these may be varied so long as theyare adequate to bring about the formation of the new complexsodium-heavy metal soap.

I am fully aware that mixtures of soda soaps and lead-fish oil soapshave heretofore been used in lubricants, particularly greases. My newproduct differs from the soaps heretofore used in that it is not amixture of thesesoaps but is a complex soap. Without intending to limitthe invention to any particular theory, it is believed the followingreactions take place to form the complex soap of the present invention.The formation of the lead oxide-fatty oil soap is believed to take placeaccording to the following formula, in which the heavy metal oxide isrepresented by lead oxide or litharge for the pur- I pose ofillustration That the above reaction probably takes place is borne outby the fact that substantially no lead glycerate appears in the finalproduct. Furthermore lubricants prepared with neutral sodium-fish oilsoap and lead-fish oil soap in admixture do not possess the heatresistant property of my improved product, or other desirableproperties, although visually the products may appear to be the same.

In the lubricant formulae given above the variety of ingredients is notgreat but it will be apparent to those skilled in the art that manyother materials may be included. For example, as indicated above, oilsoluble high molecular weight polymers may be added to impartstringiness and fillers may also be incorporated in the lubricants andother lubricant materials such as graphite, may be present if desired.Petroleum oils of any desired characteristics and in proportions adaptedto a large variety of service conditions are contemplated for use withthe new soaps, particularly the soda-lead-fish oil soaps.

Many advantages of the new soaps and greases containing them areapparent from the foregoing. Thus it has been shown that the new soapsand greases containing them have excellent resistance to hightemperature so that they are adapted for use at high temperature.Moreover, the lubricants containing the new soaps adhere tenaciously tosurfaces where applied and are accordingly adapted for use underconditions of extreme pressure. Not only do they adhere tenaciously butwhen properly compounded they are easy to apply and spread rapidlybetween the surface to be lubricated even under conditions of extremepressure. This particularly adapts these lubricants for use underconditions of extreme pressure where application is unusuallydifliicult. Because of their tenacious adherence these lubricants arealso especially suited for use on open loose running machinery wherethey are subject to a force such as centrifugal force tending to throwthem away from the surfaces requiring lubrication. They are quiteresistant to water and where this is a problem their use is furtherindicated.

It is apparent that many widely different embodiments of this inventionmay be made without departing from the spirit and scope thereof and,therefore, it is not intended to be limited except as indicated in theappended claims.

I claim:

1. The process which comprises reacting lead oxide and a fatty oil andsubsequently reacting the product so obtained with an hydroxide of ametal selected from the class consisting of alkali metals and alkalineearth metals at a sufficiently elevated temperature to substantiallyeliminate any water present in the final product whereby a complex soapof lead and a metal selected from the class consisting of alkali metalsand alkaline earth metals is formed.

2. The process of claim 1 further characterized in that the reactionsare carried out in the presence of a hydrocarbon diluent.

3. A product obtained by the process of claim 1.

4. A product obtained by the process of claim 1 when the reactions arecarried out in the presence of a hydrocarbon diluent.

5. A lubricant composition comprising a lubricating oil and the productobtained by the process of claim 1.

6. The process which comprises reacting lead oxide and a fatty oilcontaining long chain fatty acids in the presence of a hydrocarbondiluent and then reacting the product so obtained with an hydroxide of ametal selected from the group consisting of alkali metals and alkalineearth metals in the presence of a hydrocarbon diluent, said lead oxidebeing present in said first named reaction in an amount equal to fromabout 1.5 to about 3.0 molecular proportions to each molecularproportion of fatty oil.

7. A compound which is a reaction product of litharge, a fatty oil andsodium hydroxide obtained by the process of claim 6 and containing lead,the long chain of the fatty acid and sodium.

8. The product obtained by the process of claim 6.

9. A lubricant composition comprising a lubricating oil and the productobtained by the proces of claim 6.

10. The process which comprises reacting litharge and a fatty oil andthen reacting the product so obtained with sodium hydroxide at asufliciently elevated temperature to substantially eliminate any waterpresent in the final product whereby a complex sodium lead soap isformed.

11. A product obtained by the process of claim 10.

12. A lubricant composition comprising a lubricating oil and the productobtained by the process of claim 10.

13. The process which comprises reacting litharge and fish oil and thenreacting the product so obtained with sodium hydroxide at a sumcientlyelevated temperature to substantially eliminate any water present in thefinal product whereby a complex sodium lead fish oil soap is produced.

14. A product obtained by the process of claim 13.

15. The process which comprises reacting in the absence of water aboutthree molecular proportions of lead oxide and at least one molecular.proportion of a fatty oil containing fatty acids of at least eightcarbon atoms to form a lead soap of said fatty oil and subsequentlyreacting the product so formed with a hydroxide of a metal selected fromthe class consisting of alkali metals and alkaline earth metals at atemperature of from about 220 F. to about 400 F.

16. The process as described in claim 15 in which the hydroxide employedis equivalent to one mole of hydroxide per mole of lead.

17. The process described in claim 15 in which the reaction is carriedout in the presence of a petroleum oil as a diluent.

18. The product obtained by the process of claim 15.

19. A lubricating composition comprising a lubricating oil and theproduct obtained by the process of claim 15.

20. ,A lubricant composition obtained by reacting the followingingredients in the approximate specified proportions:

Parts Lead-fish oil soap (50%) 31.8 Menhaden oil 5.0 Sodium hydroxide3.0

Winkler C. C. stock (residuum stock having a Furol viscosity at 210 F.of about 850 seconds) 49.5 300 Flash L. C. T. stock (low cold test oilhaving a flash of about 300-315 F. and a Saybolt viscosity at 100 F. of80-85 seconds) 10.7

in which the lead fish oil soap is prepared by reacting three moles oflitharge with one mole of menhaden oil in the presence of a petroleumoil. said lubricant being prepared by adding a portion of the blendedmineral all together with the menhaden oil to said lead fish oil soap,heatin the mixture to a temperature of about 150 to 200 F., adding thesodium hydroxide to the mixture and heating the same to a temperature ofabout 200 to 220 F. until a heavy paste is formed, raising thetemperature to about 400 F. and subsequently adding the remainingportion of said blended mineral oil.

21. A lubricant composition obtained by reacting the followingingredients in the approximate specified proportions:

Parts Litharge 5.95 Menhaden oil 11.8 Sodium hydroxide (dry) 2.55 300flash, L. C. T. stock 29.4 Winkler C. C. stock 35.3 Heavy black 01L;15.0

in which the litharge, 1.55 parts, of the menhaden oil and parts of the300 flash L. C. T. stock are mixed at an elevated temperature until asmooth paste is formed, adding the remaining portion of the menhadenoil, a portion oi! the remaining mineral oil and the sodium hydroxide tosaid lead fish oil soap, heating the mixture to a temperature of about200 to 220 F. until a heavy paste is formed, raising the temperature toabout 400 F. to complete the reaction and subsequently blending in theremaining portion of the mineral oil.

REUBEN A. SWENSON.

